Tests on a 30 kVA class superconducting transformer

✍ Scribed by E.S. Yoneda; I. Tashiro; M. Morohoshi; D. Ito

• Book ID: 103054418
• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 424 KB
• Volume: 31
• Category: Article
• ISSN: 0011-2275
• DOI: 10.1016/0011-2275(91)90067-7

✦ Synopsis

To demonstrate the applicability of superconductors to electric power machines, the present authors made and tested a 30 kVA class single-phase superconducting transformer. The aim of the study was to determine the superconducting transformer properties. Therefore the superconducting transformer has a simple structure, i.e. the primary to secondary voltage ratio is 1:1 and the iron core is immersed in liquid helium. The core loss, evaluated from no-load tests, was 13 W and leakage impedance, obtained by short circuit tests, was 0.02 ft in accordance with a calculated value. The superconducting transformer showed the limitation effect of fault currents. The authors succeeded in continuous operation with a 0.5 ~2 load resistance. These results suggest that efficiency can be 98.5%, if the iron core is located outside the cryostat and if high T c superconductors are used as current leads. Superconducting windings exhibit training quenches in general. The authors also developed a superconducting transformer quench detector with a third winding around the iron core. The quench detector revealed that the secondary winding quenches before the primary winding.